An apparatus including a memory and a circuit. The memory may be configured to store a multidimensional array of data values. The circuit may be configured to (i) fetch a plurality of data vectors from the memory, where each of the data vectors comprises a plurality of the data values, (ii) calculate a plurality of modification values based on the data values, (iii) calculate a first value of a first window based on the data values, and (iv) calculate a second value of a second window by adding to the first value of the first window a next one of the modification values and subtracting from the first value of the first window a previous one of the modification values. The second window generally overlaps the first window in the multidimensional array along a particular axis.